The use of electrodes is well known in connection with medical instruments such as electronic medical instruments. One such instrument, for example, is a transcutaneous nerve stimulator, such as shown in U.S. Pat. No. 4,014,347. Such electronic medical instruments are active instruments and commonly utilize electrodes which are positioned so as to be engageable with, but do not penetrate, the skin of the patient to be treated, with the electrodes being driven by the instrument (i.e., the instrument provides electrical current to the electrodes and hence the electrodes are active as opposed to merely sensing a body characteristic).
While skin engageable electrodes have heretofore been suggested and/or utilized, and while such electrodes have been heretofore utilized with active devices, such electrodes have not been completely satisfactory due, at least in part, to the physical properties and/or dimensions of the electrode and/or difficulties encountered in the use of such electrodes.
With respect to electrode dimensions, at least some dimensions have been too large for effective usage or, in some cases, too small so as to cause skin burns to be suffered by the patient.
With respect to electrode properties, at least some such electrodes have lacked the necessary flexibility and/or have caused complaints due to diverse problems such as might be presented by allergies or other reactions due to adhesives and/or gels utilized.
One such problem is that due to metallic electrodes or electrodes having a substantial amount of metal adjacent to the skin, when such electrodes are used with active devices. Such electrodes can cause problems, as for example, through ionization of the metal and subsequent incorporation into the body of the patient due to current flow through the electrodes.
With respect to use of the electrodes, it has been heretofore commonly necessary to take a number of steps in order to prepare and/or place the electrodes in satisfactory skin engagement. In addition, at least in some cases, electrode use has not been fully effective due at least in part to failure to properly locate the electrodes on the skin of the patient to gain adequate conduction therethrough, which can occur, for example, if a gel is not utilized or the gel utilized is not uniform across the portion of the electrode contiguous to the skin.
In the prior art, electrodes for use with medical instruments are shown, by way of example, in U.S. Pat. Nos. 423,549; 792,066; 1,211,492; 1,889,272; 2,065,295; 3,534,727; 3,746,004; 3,817,252; 3,822,708; 3,911,930; 4,014,347; 4,026,278; 4,051,842 and 4,072,145. Of these, U.S. Pat. No. 3,746,004 is particularly directed to a disposable electrode. In addition, my U.S. patent application Ser. No. 956,770, filed Nov. 11, 1978, and entitled "Disposable Electrode" is directed to nonmetallic and nonionic electrodes for medical instruments that require a minimum of preparatory steps for usage.
With respect to electrode usage, however, it has still often been necessary to remove the electrodes after a relatively short period of time to alleviate problems due to virtual sealing of the skin covered by the electrode. Thus, electrodes, and particularly disposable electrodes, could not heretofore be utilized as effectively as might be the case where air could come into skin contact as is necessary, at least with respect to many patients, to avoid, or at least alleviate, skin problems induced by sealing of the skin against air contact.
It has also been found desirable to provide an electrical lead one end of which is either permanently adhered to the electrode or at least can easily be connected thereto in a manner such that the lead does not become easily disconnected during use by a patient. Likewise, it has also been found desirable to provide a connection at the other end of the electrode whereby a patient can easily connect the electrode to the electrical instrument and easily disconnect the same therefrom.